feat(fleet): auto-enable units on install + drift recognizes wrapped runtimes

- mosaic fleet install now enables mosaic-tmux-holder.service and
  mosaic-agent@<name>.service via systemctl --user enable after copying
  unit files; enabling is non-fatal (warns and continues on failure)
- best-effort loginctl enable-linger for logout survival
- --no-enable flag opts out of auto-enable
- detectDrift updated to use RUNTIME_ACCEPTABLE_COMMANDS map:
  pi/codex/opencode/claude accept 'node' (mosaic yolo wrapper);
  dogfood accepts python3/python; canary-pi (runtime=pi, pane=python3)
  still correctly flags DRIFT

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01RMoEx7hfdFGjUiCHuN1RRi

packages/mosaic/src/commands/fleet.spec.ts

@@ -10,11 +10,14 @@ import {
   buildAgentWatchCreateViewerCommand,
   buildAgentWatchKillViewerCommand,
   buildAgentVerifyAcceptedCommand,
+  buildEnableLingerCommand,
   buildFleetServiceCommand,
+  buildSystemdEnableCommand,
   buildSystemdShowCommand,
   buildTmuxListPanesCommand,
   classifySendResult,
   detectDrift,
+  enableFleetUnits,
   generateAgentEnv,
   getDefaultOperatorSourceLabel,
   getDefaultTenantAndHost,
@@ -28,10 +31,12 @@ import {
   parseTmuxListPanes,
   registerFleetCommand,
   resolveFleetPaths,
+  RUNTIME_ACCEPTABLE_COMMANDS,
   VERIFY_DEFAULT_TIMEOUT_MS,
   VERIFY_POLL_INTERVAL_MS,
   type AgentPsRow,
   type CommandRunner,
+  type FleetRoster,
   type InteractiveRunner,
   type SleepFn,
 } from './fleet.js';
@@ -909,6 +914,118 @@ describe('fleet ps — drift detection', () => {
   it('does NOT flag drift when pane command is null (pane dead)', () => {
     expect(detectDrift('pi', null)).toBe(false);
   });
+
+  it('does NOT flag drift when pane=node for wrapped pi agent (mosaic yolo pi)', () => {
+    expect(detectDrift('pi', 'node')).toBe(false);
+  });
+
+  it('does NOT flag drift when pane=node for wrapped codex agent (mosaic yolo codex)', () => {
+    expect(detectDrift('codex', 'node')).toBe(false);
+  });
+
+  it('flags drift when pane=python3 for pi runtime (canary-pi dogfood regression guard)', () => {
+    expect(detectDrift('pi', 'python3')).toBe(true);
+  });
+
+  it('does NOT flag drift when pane=python3 for dogfood runtime', () => {
+    expect(detectDrift('dogfood', 'python3')).toBe(false);
+  });
+
+  it('flags drift for unknown pane command on known runtime', () => {
+    expect(detectDrift('claude', 'bash')).toBe(true);
+  });
+
+  it('RUNTIME_ACCEPTABLE_COMMANDS is exported and contains expected entries', () => {
+    expect(RUNTIME_ACCEPTABLE_COMMANDS['pi']).toContain('node');
+    expect(RUNTIME_ACCEPTABLE_COMMANDS['pi']).not.toContain('python3');
+    expect(RUNTIME_ACCEPTABLE_COMMANDS['dogfood']).toContain('python3');
+    expect(RUNTIME_ACCEPTABLE_COMMANDS['codex']).toContain('node');
+  });
+});
+
+describe('fleet install — auto-enable units for boot-survival', () => {
+  it('buildSystemdEnableCommand and buildEnableLingerCommand return correct command arrays', () => {
+    expect(buildSystemdEnableCommand('mosaic-tmux-holder.service')).toEqual([
+      'systemctl',
+      '--user',
+      'enable',
+      'mosaic-tmux-holder.service',
+    ]);
+    expect(buildEnableLingerCommand('testuser')).toEqual(['loginctl', 'enable-linger', 'testuser']);
+  });
+
+  it('enables holder and each agent unit via injected runner after install', async () => {
+    const minimalRoster: FleetRoster = {
+      version: 1,
+      transport: 'tmux',
+      tmux: { socketName: 'mosaic-factory', holderSession: '_holder' },
+      defaults: { workingDirectory: '~/src' },
+      runtimes: { codex: { resetCommand: '/clear' } },
+      agents: [{ name: 'coder0', runtime: 'codex', className: 'worker' }],
+    };
+
+    const calls: string[][] = [];
+    const runner: CommandRunner = async (command, args) => {
+      calls.push([command, ...args]);
+      return { stdout: '', stderr: '', exitCode: 0 };
+    };
+
+    await enableFleetUnits(runner, minimalRoster, {});
+
+    expect(calls).toContainEqual(['systemctl', '--user', 'enable', 'mosaic-tmux-holder.service']);
+    expect(calls).toContainEqual(['systemctl', '--user', 'enable', 'mosaic-agent@coder0.service']);
+  });
+
+  it('install still succeeds when systemctl enable returns non-zero (non-fatal)', async () => {
+    const minimalRoster: FleetRoster = {
+      version: 1,
+      transport: 'tmux',
+      tmux: { socketName: 'mosaic-factory', holderSession: '_holder' },
+      defaults: { workingDirectory: '~/src' },
+      runtimes: { codex: { resetCommand: '/clear' } },
+      agents: [{ name: 'coder0', runtime: 'codex', className: 'worker' }],
+    };
+
+    const calls: string[][] = [];
+    const runner: CommandRunner = async (command, args) => {
+      calls.push([command, ...args]);
+      // Simulate systemctl enable failure
+      if (command === 'systemctl' && args.includes('enable')) {
+        return { stdout: '', stderr: 'Unit not found', exitCode: 1 };
+      }
+      return { stdout: '', stderr: '', exitCode: 0 };
+    };
+
+    // Must NOT reject/throw even when enable calls fail
+    await expect(enableFleetUnits(runner, minimalRoster, {})).resolves.toBeUndefined();
+
+    // The enable attempt must have been made
+    expect(calls.some((c) => c.includes('enable'))).toBe(true);
+  });
+
+  it('--no-enable skips all systemctl enable and loginctl linger calls', async () => {
+    const minimalRoster: FleetRoster = {
+      version: 1,
+      transport: 'tmux',
+      tmux: { socketName: 'mosaic-factory', holderSession: '_holder' },
+      defaults: { workingDirectory: '~/src' },
+      runtimes: { codex: { resetCommand: '/clear' } },
+      agents: [{ name: 'coder0', runtime: 'codex', className: 'worker' }],
+    };
+
+    const calls: string[][] = [];
+    const runner: CommandRunner = async (command, args) => {
+      calls.push([command, ...args]);
+      return { stdout: '', stderr: '', exitCode: 0 };
+    };
+
+    await enableFleetUnits(runner, minimalRoster, { enable: false });
+
+    // No calls should include 'enable'
+    expect(calls.every((c) => !c.includes('enable'))).toBe(true);
+    // No loginctl calls at all
+    expect(calls.every((c) => c[0] !== 'loginctl')).toBe(true);
+  });
 });
 
 describe('fleet ps — tenant and host', () => {

packages/mosaic/src/commands/fleet.ts

@@ -210,6 +210,93 @@ export function buildFleetServiceCommand(action: FleetServiceAction, agentName?:
   return ['systemctl', '--user', action, service];
 }
 
+/**
+ * Returns the systemctl --user enable command for a given unit.
+ * Used by the install auto-enable step to persist units across reboots.
+ */
+export function buildSystemdEnableCommand(unit: string): string[] {
+  return ['systemctl', '--user', 'enable', unit];
+}
+
+/**
+ * Returns the loginctl enable-linger command for a given user.
+ * Linger allows user systemd services to survive logout.
+ */
+export function buildEnableLingerCommand(user: string): string[] {
+  return ['loginctl', 'enable-linger', user];
+}
+
+/**
+ * Enable fleet units for boot-survival after install.
+ * Non-fatal: if systemctl enable returns non-zero, a warning is printed and we continue.
+ * If opts.enable === false (--no-enable flag), the whole step is skipped.
+ */
+export async function enableFleetUnits(
+  runner: CommandRunner,
+  roster: FleetRoster,
+  opts: { enable?: boolean },
+): Promise<void> {
+  if (opts.enable === false) {
+    return;
+  }
+  try {
+    let succeeded = 0;
+    let failed = 0;
+
+    const holderResult = await runner(
+      ...splitCommand(buildSystemdEnableCommand('mosaic-tmux-holder.service')),
+    );
+    if (holderResult.exitCode === 0) {
+      succeeded++;
+    } else {
+      failed++;
+      process.stderr.write(
+        `Warning: could not enable mosaic-tmux-holder.service: ${holderResult.stderr || holderResult.stdout || 'non-zero exit'}\n`,
+      );
+    }
+
+    for (const agent of roster.agents) {
+      const unit = `mosaic-agent@${agent.name}.service`;
+      const result = await runner(...splitCommand(buildSystemdEnableCommand(unit)));
+      if (result.exitCode === 0) {
+        succeeded++;
+      } else {
+        failed++;
+        process.stderr.write(
+          `Warning: could not enable ${unit}: ${result.stderr || result.stdout || 'non-zero exit'}\n`,
+        );
+      }
+    }
+
+    if (succeeded > 0) {
+      console.log(`Enabled ${succeeded} unit(s) for boot-survival.`);
+    }
+    if (failed > 0) {
+      process.stderr.write(
+        `Warning: ${failed} unit(s) could not be enabled (systemctl unavailable?). Run manually if needed.\n`,
+      );
+    }
+
+    // Best-effort linger
+    let username: string;
+    try {
+      username = userInfo().username;
+    } catch {
+      username = process.env['USER'] ?? process.env['LOGNAME'] ?? 'unknown';
+    }
+    const lingerResult = await runner(...splitCommand(buildEnableLingerCommand(username)));
+    if (lingerResult.exitCode !== 0) {
+      process.stderr.write(
+        `Hint: run 'loginctl enable-linger ${username}' as root to survive logout.\n`,
+      );
+    }
+  } catch (err) {
+    process.stderr.write(
+      `Warning: auto-enable step failed unexpectedly: ${err instanceof Error ? err.message : String(err)}\n`,
+    );
+  }
+}
+
 export function buildAgentSendCommand(
   paths: FleetPaths,
   agentName: string,
@@ -437,32 +524,41 @@ export function parseTmuxListPanes(
   return { pid, command, dead, idleSeconds };
 }
 
+/**
+ * Maps each known runtime to the set of acceptable pane commands.
+ * A pane running any of these commands for the given runtime is NOT considered drifted.
+ * Runtimes launched via `mosaic yolo` wrap in node, so 'node' is acceptable for most.
+ * The dogfood runtime accepts python3/python (the canary-pi dogfood stub).
+ */
+export const RUNTIME_ACCEPTABLE_COMMANDS: Record<string, readonly string[]> = {
+  claude: ['claude', 'node'],
+  codex: ['codex', 'node'],
+  opencode: ['opencode', 'node'],
+  pi: ['pi', 'node'],
+  dogfood: ['python3', 'python'],
+};
+
 /**
  * Determine if there is a runtime drift: roster says one runtime but the pane
  * is actually running something from a different runtime. We detect this by
- * checking if the pane command doesn't match a known canonical command for the
+ * checking if the pane command doesn't match a known acceptable command for the
  * roster's declared runtime.
  *
- * Known canonical commands per runtime:
+ * Known acceptable commands per runtime (see RUNTIME_ACCEPTABLE_COMMANDS):
- *   claude → claude
+ *   claude   → claude, node  (node covers mosaic yolo wrapper)
- *   codex  → codex
+ *   codex    → codex, node
- *   opencode → opencode
+ *   opencode → opencode, node
- *   pi     → pi
+ *   pi       → pi, node      (python3 still flags drift for canary-pi dogfood stub)
+ *   dogfood  → python3, python
  *
  * If the pane is running something else (e.g., python3/dogfood-agent.py) for
  * an agent whose roster runtime is "pi", that's a drift.
  */
 export function detectDrift(rosterRuntime: string, paneCommand: string | null): boolean {
   if (!paneCommand) return false;
-  const knownCommands: Record<string, string[]> = {
+  const acceptable = RUNTIME_ACCEPTABLE_COMMANDS[rosterRuntime];
-    claude: ['claude'],
+  if (!acceptable) return false;
-    codex: ['codex'],
+  return !acceptable.includes(paneCommand);
-    opencode: ['opencode'],
-    pi: ['pi'],
-  };
-  const expected = knownCommands[rosterRuntime];
-  if (!expected) return false;
-  return !expected.includes(paneCommand);
 }
 
 /**
@@ -706,12 +802,22 @@ export function registerFleetCommand(program: Command, deps: FleetCommandDeps =
   cmd
     .command('install')
     .description('Install local fleet tools and user systemd units')
-    .action(async () => installFleet(cmd, frameworkRoot));
+    .option('--no-enable', 'Skip enabling units for boot-survival')
+    .action(async (opts: { enable?: boolean }) => {
+      await installFleet(cmd, frameworkRoot);
+      const roster = await loadRosterForCommand(cmd);
+      await enableFleetUnits(runner, roster, opts);
+    });
 
   cmd
     .command('install-systemd')
     .description('Install local fleet tools and user systemd units')
-    .action(async () => installFleet(cmd, frameworkRoot));
+    .option('--no-enable', 'Skip enabling units for boot-survival')
+    .action(async (opts: { enable?: boolean }) => {
+      await installFleet(cmd, frameworkRoot);
+      const roster = await loadRosterForCommand(cmd);
+      await enableFleetUnits(runner, roster, opts);
+    });
 
   for (const action of ['start', 'stop', 'restart'] as const) {
     cmd